谁能证明被注释掉的贪心代码和没注释掉的是等效的？（$A$ 和 $B$ 处）

#include<bits/stdc++.h>
using namespace std;
const int N=5e5+5;
int n,a[N],x[N],y[N],ans;
void solve(){
    int m1=0,m2=0,i,top=0;
    for(i=1;i<=n;i++){
        if(a[i]>a[top]) top=i;
        x[i]=INT_MAX;
    }
    for(i=n;i>top;i--){
        if(m1<a[i]) m1=a[i];
        else if(m2<a[i]) m2=a[i];
        else break;
        x[i]=m2,y[i]=m1;
    }
    m1=m2=0;
    for(i=1;i<=top;i++)
        if(m1<a[i]) m1=a[i];
        else if(m2<a[i]) m2=a[i];
        else return;
    for(;i<=n;i++){
        //A
        if(x[i]==a[i]) ans+=(m2<x[i]&&m1>y[i]);
        else if(y[i]==a[i]) ans+=(m2<y[i]&&m1>x[i]);

        if(m2<a[i]&&(m1<a[i]||a[i]<a[i+1])) m2=a[i];
        else if(m1>a[i]) m1=a[i]; 
        else return;
        //B
        // ans+=(m1>x[i]&&m2<=y[i]);
    }
}
int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin>>n;
    for(int i=1;i<=n;i++) cin>>a[i];
    solve(),reverse(a+1,a+n+1),solve();
    cout<<ans;
    return 0;
}